which way is distributor cap supposed to face on 88 tbi

[chevyguy82]

just figured out my problems with my tbi conversion. i had a huge vacuum leak. now i need to know which way the distributor cap is supposed to face. i can rotate my new distributor 360 degrees while the rotor stays pointed at #1 top dead center. where do i intall the number one spark plug wire? where is the placemant of the plugs on the distributor? thanks for the help.

 

[4X4HIGH]

The plugs face about a 2 O'clock position when looking from the front bumper into the engine compartment.

 

[chevyguy82]

wow, you must be on here all the time. i wish you were my neighbor. so you are saying the distributor should face to the right?

 

[4X4HIGH]

wow, you must be on here all the time. i wish you were my neighbor. so you are saying the distributor should face to the right?

If i'm not working and don't have anything to do then YES i'm usually on here.

Here is a pic of my engine before I installed it. Look carefully and you should be able to judge where the dizzy needs to point to be in the factory position.

 

[chevyguy82]

it won't let me see it. i just tried to turn the cap to where the plugs face 2 oclock and then set up my plug wires being #1 at front right. should i start #1 just past the right plug in on the distributor?

 

[4X4HIGH]

With the distributor installed as I said (plugs facing about the 2 O'clock position) that should put 2 terminals facing forward and the one on the driverside in front of the hold down screw for the cap is #1 terminal.

 

[chevyguy82]

thankyou so much for your help. i'll try it in the morning and see. don't ever buy a tbi to carb intake adaptor. it took forever to find my leak. the problem i am having now is it runs great and smooth except a little back firing. it will even light up the tires in driveway. it never did that before with the carb. i did not think the cap was on right. i will let you know tomorrow first thing what happens.

 

[4X4HIGH]

thankyou so much for your help. i'll try it in the morning and see. don't ever buy a tbi to carb intake adaptor. it took forever to find my leak. the problem i am having now is it runs great and smooth except a little back firing. it will even light up the tires in driveway. it never did that before with the carb. i did not think the cap was on right. i will let you know tomorrow first thing what happens.

You have that backwards. I don't usually buy anything like that though as I have a friend who makes that kind of stuff for me on a CNC.

 

[tRustyK5]

funny, my 90 has the plugs at the 2 o clock position. My buddy is here today with an 89 that will not idle, a problem that has gotten progressively worse over the last few weeks. I have a lot of known working TBI parts here on my 90 and a spare engine I have from an 87. I'll spare all the details other than we eventually found his distributor was self destructing.

We checked rotor position, pulled the old distributor out and swapped the new one in, rotor in the same spot. New cap, rotor, wires and plugs. I set the distributor at about the 2:30 position (in reference to the plugs) and it started hard and ran bad. Too advanced. Moved it to 3:00, started a bit better but still ran bad. Moved to 4:00 and it started easy and ran pretty good. Finished at about 4:30 and right now it's running 95% or better. Got too late to put a light on it. This is with the number one lead pretty much right over the hold down screw.

Rene

 

[4X4HIGH]

funny, my 90 has the plugs at the 2 o clock position. My buddy is here today with an 89 that will not idle, a problem that has gotten progressively worse over the last few weeks. I have a lot of known working TBI parts here on my 90 and a spare engine I have from an 87. I'll spare all the details other than we eventually found his distributor was self destructing.

We checked rotor position, pulled the old distributor out and swapped the new one in, rotor in the same spot. New cap, rotor, wires and plugs. I set the distributor at about the 2:30 position (in reference to the plugs) and it started hard and ran bad. Too advanced. Moved it to 3:00, started a bit better but still ran bad. Moved to 4:00 and it started easy and ran pretty good. Finished at about 4:30 and right now it's running 95% or better. Got too late to put a light on it. This is with the number one lead pretty much right over the hold down screw.

Rene

Sounds like your buddy might have a timing chain that is really stretched and or has jumped a few teeth on the cam gear. That would explain why you would have to rotate the distributor that far in order to make it run decent.

 

[tRustyK5]

Don't think so. The motor only has about 70,000 miles on it.

We've had a few high miler's with sloppy chains and had to advance indicated timing to make em run where they wanted to run best (on '75 Grand Prix with 200K+ that ran best 18 degrees more advanced than factory specs). In this case the distributor has been retarded farther...opposite of what a motor with a stretched chain wants.

It is possible the engine was put together with the dist one tooth off and the cap wiring adjusted to compensate. My buddy has gone home so I can't go double check that.

It is somewhat less relevant than the older vac advance distributors...

Rene

 

[chevyguy82]

well went out this morning and put distributor at 2 oclock and #1 plug over screw and it fired right up. nice and smooth when revving. it idles way too low. it will run for about 30 seconds then just die while idling, not enough time to get a timing light on it. what would cause it to die all of a sudden? if i give it gas when it begins to die it will keep on running for another 30 seconds.

 

[chevyguy82]

i now have backfiring out of the throttle body. i adjusted the torx screw to raise the idle. it will idle but no matter how i turn the distributor it will backfire out of the throttle body. i also found i don't have two wires hooked up to computer. they both register 5 volts, pink with black stripe. where do these wires go? i have 12 volts to iac also. should it be only 5?

 

[Keitha]

Compression test...

 

[Fordum]

If it is dieing when you give it gas, check your fuel flow/pressure.

Also, check your oil pressure switch. It sounds like your fuel pump is cutting off.
The oil pressure switch is supposed to keep the fuel pump going as long as there is oil pressure.

 

[mrdrinksalil]

i now have backfiring out of the throttle body. i adjusted the torx screw to raise the idle. it will idle but no matter how i turn the distributor it will backfire out of the throttle body. i also found i don't have two wires hooked up to computer. they both register 5 volts, pink with black stripe. where do these wires go? i have 12 volts to iac also. should it be only 5?

First I'd go though some basic voltage checks. If you are running the 7747 ECM, see the attached voltage checks on post #2 here
http://www.binderplanet.com/forums/showthread.php?t=45293

If you are backfiring out the throttle body and you can't adjust it out with the timing you are probably running lean.

Get the timing set correctly (set at 0 Deg. with the bypass wire unplugged) and check your fuel pressure (between 12-14 psi and should not change with RPM or load).

see here
http://www.binderplanet.com/forums/showthread.php?p=345737#post345737

 

[Fordum]

FWIW, I looked at a schematic for an 87, and the pink with black wire went to the idle stop solenoid.
Suspect you don't have one of those anymore, since it was part of the carb system.

 

[chevyguy82]

fuel pressure is 13 psi all the time, it never changes. brand new fuel pump. if i pinch the return line it pegs the gauge. the pink with black wire came with the new harness into the truck. also this motor maybe has 1000 miles on it. it was actually a brand new gm crate 350.